We propose a United States-Peru collaboration to examine two common infections of major public health importance in female commercial sex workers (CSW): human papilloma virus (HPV) and human T-cell lymphotropic virus types 1 and 2 (HTLV). The research would be conducted in Peru at the U.S. Naval Medical Research Center Detachment and the Centra de Salud "Alberto Barton" del Callao in collaboration with Dr. Silvia Montano, as an extension of NIH grant #R01NS055627-01, entitled Retrovirus Infections of the Nervous System in Peru. CSW are at increased risk for sexually transmitted infections (STI), particularly those who do not receive routine medical care or who migrate for sex work from other Andean countries. Although both HPV and HTLV carry significant potential health consequences, such as cervical cancer and HTLV-l-associated myelopathy, no prevention programs currently exist in Peru. The aims of this study are to determine the prevalence and determinants of HPV and HTLV infections in CSW, to define the acquisition of HPV strain types in CSW initiating sex work, and examine the correlates of cervico-vaginal shedding of HPV and HTLV infections. The proposed study would address these aims through: 1) A cross-sectional study of migrant CSW receiving care at CSAB and via a mobile clinic, as well as an equal number of Peruvian CSW. Participants will receive a structured, face-to-face interview administered by a social worker regarding demographic, migration and economic characteristics, medical history, sexual behavior (including sexual networks and STI/HIV knowledge) and work practices. Cervical and serological samples will be obtained to test for HPV,HTLV, and other STI. Digital colposcopy will be performed to evaluate for cervical ectopy. 2) A prospective study of CSW who initiated sex work within the last two months. One hundred fifty participants will each receive quarterly HPV testing for one year. 3) A collection of 50 stored cervical brush samples will be analyzed for HPV and correlated with digital colposcopic findings and STI information. The proposed study would define HPV and HTLV prevalences among CSW in Peru, provide additional information regarding acquisition, shedding and transmission of HPV and HTLV infections in women at highest risk for these infections, and elucidate risk factors that could be used to develop prevention policies in Peru and other countries with women at high risk for these infections.